Authors: William Tintor*, University of Arizona, Connie Woodhouse, University of of Arizona
Topics: Paleoenvironmental Change, Biogeography
Keywords: Dendrochronology, Dendroclimatology, Climate Reconstruction
Session Type: Poster
Presentation File: No File Uploaded
Overshadowed by the more charismatic Great Basin Bristlecone Pine (Pinus Longaeva), Rocky Mountain Bristlecone Pine (Pinus aristata) provides valuable insight into the climate of the central Rocky Mountains of Colorado and New Mexico. With 2500 year-old living trees and remnants dating back 2800 years, this "shorter-lived" taxon of the bristlecone family still has immense potential for valuable climate reconstruction. As with P. longaeva, the extremely slow growth of P. aristata results in long-term smoothing of climate information. Annual precipitation signals mix with low-frequency temperature responses within individual trees. Adjacent trees have a mix of climate sensitivities related to variable topographic and elevational characteristics of the site. Older trees at high elevations persist though changes in tree line, resulting in a shifting tree response to climate, becoming sensitive to temperatures when the current upper tree line coincides with their location. Because their climate sensitivities depend on microsite characteristics and long-term shifts in climate, an abundance of caution must be taken when using P. aristata chronologies in climate reconstructions.
Using 4 previous and 8 new/updated P. aristata collections from -846-2018 CE, our study examines climate correlations contained within the trees. Empirical orthogonal function analysis is applied to individual tree-core ring-width measurements, decomposing intermixed climate signals. Intra-site comparison is conducted to evaluate the spatial-temporal shifts in ring-width correlation among the multiple sites as a potential avenue for evaluating shifting climate sensitivities prior to the modern historic records. Finally, we highlight the strengths and challenges of P. aristata for use in dendroclimatic reconstruction.